1. Field of the Invention
The present invention relates to an improvement on the cartridge accommodating device of a camera and the cartridge chamber lid of the camera.
2. Description of Related Art
After a camera is loaded with a film cartridge, the film cartridge is generally held at a predetermined position in the following manner. For example, the spool shaft of the film cartridge is vertically held from above and below by a pair of holding shafts, and the pressure of an urging member such as a spring is applied from one of the holding shafts to the spool shaft to hold in place the film cartridge. This mechanism was disclosed in Japanese Laid-Open Patent Application No. Hei 7-168318, etc.
In this mechanism, one of the pair of holding shafts is in the form of a fork arranged to transmit the driving force of a motor to the spool shaft of the film cartridge. The other holding shaft is mounted on the cartridge chamber lid. When the cartridge chamber lid is closed after the film cartridge is loaded, the spool shaft of the film cartridge is held by the holding shaft which is under the urging force of the spring or the like.
In the above-stated arrangement, the fork is provided with a key, and the spool shaft of the film cartridge is provided with a key way for engaging the key of the fork. Before the key comes to engage the key way, the fork runs idle in the state of retreating from the key way and does not cause the spool shaft of the film cartridge to rotate. The spool shaft of the film cartridge comes to rotate together with the fork after the key engages the key way.
Further, in an arrangement disclosed in Japanese Laid-Open Patent Application No. Hei 7-325337, a film transport transmission mechanism is disposed on the bottom side of a camera while a fork is disposed on the cartridge chamber lid of the camera.
With respect to the camera arranged in that manner, however, nothing has been disclosed as to such an arrangement that the fork and a shaft keep member arranged to retain in place the spool shaft part of the film cartridge are disposed on the cartridge chamber lid to apply an urging force from the side of the cartridge chamber lid to the spool shaft of the film cartridge while a film is being transported.
Some of known cameras are arranged such that, with a fork provided on a cartridge chamber lid, an urging force is arranged to be received by the bottom surface of a film cartridge. However, in the case of the camera of that type, the position of the film cartridge tends to become unstable, because no urging force is applied to the spool shaft of the film cartridge.
Meanwhile, the camera of the kind using a conventional film measuring 35 mm in width generally has a fork arranged to be composed of a key and a shaft keep member in one body, in which the key moves back and forth in the direction of the spool shaft of the film cartridge and, at the same time, pushes the spool shaft of the film cartridge. The fork of the type having a key and a shaft keep member in one body is advantageous in that its arrangement permits use of only one urging member such as a spring. However, in the fork of this type, since a key returning force, with which the key returns from the retreated position, is the same as a shaft urging force, with which the key pushes the spool shaft, there is the possibility that a problem arises in the case of a camera in which the key returning force and the shaft urging force are different from each other. If the key returning force obtained by adjusting it to the shaft urging force is too strong, either the spool shaft tends to be caused to rotate by a frictional force without the key engaging the key way or a load on the mechanism increases before the key comes to engage the key way.
In accordance with one aspect of the invention, there is provided a cartridge accommodating device of a camera, in which a key member can be caused to smoothly engage a key way and a film cartridge can be stably held in a predetermined position so as to smoothly transport a film.
The above and other aspects of the invention will become apparent from the following detailed description of a preferred embodiment thereof taken in connection with the accompanying drawings.